1.. SPDX-License-Identifier: GPL-2.0+
2.. Copyright (c) 2013 The Chromium OS Authors.
3
4Version information
5===================
6
7U-Boot releases are named by year and patch level, for example 2020.10 means the
8release that came out in October 2020. Release candidates are tagged every few
9weeks as the project heads to the next release. So 2020.10-rc1 was the first
10release candidate (RC), tagged soon after 2020.07 was released.
11
12See https://www.denx.de/wiki/view/U-Boot/ReleaseCycle for full details.
13
14Within the build system, various Makefile variables are created, making use of
15VERSION, PATCHLEVEL and EXTRAVERSION defined at the top of 'Makefile'. There is
16also SUBLEVEL available for downstream use. See also CONFIG_IDENT_STRING.
17
18Some variables end up in a generated header file at
19include/generated/version_autogenerated.h and can be accessed from C source by
20including <version.h>
21
22The following are available:
23
24   UBOOTRELEASE (Makefile)
25      Full release version as a string. If this is not a tagged release, it also
26      includes the number of commits since the last tag as well as the the git
27      hash.  If there are uncommitted changes a '-dirty' suffix is added too.
28
29      This is written by scripts/setlocalversion (maintained by Linux) to
30      include/config/uboot.release and ends up in the UBOOTRELEASE Makefile
31      variable.
32
33      Examples::
34
35         2020.10-rc3
36         2021.01-rc5-00248-g60dd854f3ba-dirty
37
38   PLAIN_VERSION (string #define)
39      This is UBOOTRELEASE but available in C source.
40
41      Examples::
42
43         2020.10
44         2021.01-rc5-00248-g60dd854f3ba-dirty
45
46   UBOOTVERSION (Makefile)
47      This holds just the first three components of UBOOTRELEASE (i.e. not the
48      git hash, etc.)
49
50      Examples::
51
52         2020.10
53         2021.01-rc5
54
55   U_BOOT_VERSION (string #define)
56      "U-Boot " followed by UBOOTRELEASE, for example::
57
58         U-Boot 2020.10
59         U-Boot 2021.01-rc5
60
61      This is used as part of the banner string when U-Boot starts.
62
63   U_BOOT_VERSION_STRING (string #define)
64      U_BOOT_VERSION followed by build-time information
65      and CONFIG_IDENT_STRING.
66
67      Examples::
68
69         U-Boot 2020.10 (Jan 06 2021 - 08:50:36 -0700)
70         U-Boot 2021.01-rc5-00248-g60dd854f3ba-dirty (Jan 06 2021 - 08:50:36 -0700) for spring
71
72   U_BOOT_VERSION_NUM (integer #define)
73      Release year, e.g. 2021 for release 2021.01. Note
74      this is an integer, not a string.
75
76   U_BOOT_VERSION_NUM_PATCH (integer #define)
77      Patch number, e.g. 1 for release 2020.01. Note
78      this is an integer, not a string.
79
80Build date/time is also included. See the generated file
81include/generated/timestamp_autogenerated.h for the available
82fields. For example::
83
84   #define U_BOOT_DATE "Jan 06 2021"     (US format only)
85   #define U_BOOT_TIME "08:50:36"        (24-hour clock)
86   #define U_BOOT_TZ "-0700"             (Time zone in hours)
87   #define U_BOOT_DMI_DATE "01/06/2021"  (US format only)
88   #define U_BOOT_BUILD_DATE 0x20210106  (hex yyyymmdd format)
89   #define U_BOOT_EPOCH 1609948236
90
91The Epoch is the number of seconds since midnight on 1/1/70. You can convert
92this to a time with::
93
94   $ date -u -d @1609948236
95   Wed 06 Jan 2021 03:50:36 PM UTC
96   $ date -d 'Wed 06 Jan 2021 03:50:36 PM UTC' +%s
97   1609948236
98
99Every time you build U-Boot this will update based on the time
100on your build machine. See 'Reproducible builds' if you want to
101avoid that.
102